Spiny Dogfish Shark

The spiny dogfish shark is the most abundant shark. This small shark is also known as the piked dogfish, skittledog, spotted dogfish, white-spotted dogfish, codshark, and thorndog. Its dorsal fin has spines that are mildly poisonous. More is known about it than any other species of shark; it is often studied in scientific laboratories. It is used extensively by people as food, fertilizer, hide, pet food, and liver oil.
The spiny dogfish shark is a small shark that is deep gray with some white spots; the belly is off-white. It had two dorsal fins, each preceded by a mildly poisonous spin. It has a short snout, large eyes and no anal fin.
TEETH
The smooth teeth are located in rows which rotate into use as needed. The first two rows are used in obtaining prey, the other rows rotate into place as they are needed. As teeth are lost, broken, or worn down, they are replaced by new teeth that rotate into place.
SIZE
Spiny dogfish sharks average 3-4 feet (0.9-1.2 m) long.
DIET AND FEEDING HABITS
It eats mostly fish (including other sharks), but also eats squid and octopus.
SPINY DOGFISH SHARK ATTACKS
Dogfish are not considered to be dangerous, but some damage could be done by their teeth and their slightly poisonous dorsal fin spines.
SOCIAL GROUPS
Spiny dogfish sharks are gregarious (social) and travel in schools of hundreds to thousands of individuals. These schools are sometimes segregated by sex and age. They are called dogfish because they travel and hunt in packs. They also migrate in schools, following cool waters.
HABITAT
The spiny dogfish shark stays in water that is between 45°F - 59°F (7°C - 15°C). It will venture into brackish waters. Dogfish are mostly bottom-dwellers, dwelling in depths from the surface down to 400 fathoms (2,400 feet).
DISTRIBUTION
The spiny dogfish shark is found worldwide in temperate and subarctic waters, in the temperate and subarctic latitudes of the North Atlantic and North Pacific oceans. These sharks have even been found in the Black sea and Mediterranean sea.

Smooth Dogfish Shark

The smooth dogfish has a slender body with an obvious spiracle behind the eye. The caudal fin has a rounded lower lobe and a larger top lobe. The teeth are very small, blunt, numerous and similar in both the upper and lower jaw. This shark is olive gray or brown on top and yellow or grayish white below. The smooth dogfish is able to change its colour slowly through contraction of melanophores (migratory pigment cells that through contraction or relaxation give the impression of a colour change). This shark grows to 1.5 meters (5 feet) in length. It is primarily nocturnal.
This shark is a scavenger and opportunistic feeder, but regularly feeds upon crabs, lobster and shrimp.
The smooth dogfish is a viviparous shark giving birth to a litter of 10 to 20 pups. Gestation is 10 months long and the young are usually delivered in the summer months. The pups are 34 to 39 cm (13 to 15 inches) at birth. Sexual maturity is reached when individuals reach 85 cm (33 inches) in length.
This shark commonly lives in bays and inshore waters. It prefers waters less than 18 meters (60 feet) deep. The smooth dogfish is a migratory species that moves north and south with the seasons.
This species of shark occurs in the western Atlantic Ocean. It ranges from the Bay of Fundy to Uruguay. It is a common shark in the waters off Cape Cod to Delaware Bay, and overwinters from Chesapeake Bay to South Carolina. It is rare in Canadian waters and the Bay of Fundy represents the northern most part of its range.

Silky Shark

The silky shark, Carcharhinus falciformis, is a large pelagic shark of tropical and warm temperate seas.
This species is found worldwide in tropical and warm temperate (> 23 °C) seas. It is usually pelagic, but sometimes approaches the coast, especially at remote offshore islands. It is found to depths of at least 500 m.
This shark has a large 'typical' shark body, slender with 'silky' smooth skin. It is brown-grey dorsally and white below with no special markings. It can be distinguished from other sharks by the second dorsal fin, which has a very long free tip at the rear, about two and a half times the fin height. The first dorsal fin is also farther back than on any other carcharhiniform, beginning behind the pectoral fins.[1]
The maximum size is 3.3 m, but the length is usually not more than 2.4 m.
The silky shark is a predator. It feeds mainly on inshore and pelagic bony fishes, but also eats squid and pelagic crab.

Shortfin Mako Shark

The shortfin mako shark is a sleek spindle shaped shark with a long conical snout. This shark has short pectoral fins and a crescent shaped caudal (tail) fin. There is a distinct caudal keel on the caudal base. Its second dorsal fin is much smaller than the first. The teeth are are slender and slightly curved with no lateral cusps, and are visible even when the mouth is closed. There is marked countershading on this shark: dorsally it is a metallic indigo blue while ventrally it is white.
The shortfin mako can grow to lengths of 3.9 meters (13 feet). There is still some uncertainty about its life-span, but it is suspected to reach ages of between 11-23 years.
As one of the fastest sharks in the ocean, this powerful shark can attain burst swimming speeds of up to 35 km/h (22 mph) and can leap clear of the water to heights of up to 6 meters (20 feet). These qualities have made this species a sought after sport fish in some parts of its range.
The shortfin mako feeds mainly upon bony fishes including mackerels, tunas, bonitos and swordfish, but may also eat other sharks, porpoises and sea turtles.
Reproduction
Female shortfin makos usually become sexually mature at a length of 3 meters. Developing embryos feed on unfertilized eggs in the uterus during the gestation period of 15-18 months. The 4-18 surviving young are born live in the late winter and early spring at a length of about 70 cm, but have no placental connection during development (ovoviviparity). It is believed that females may rest for 18 months after birth before the next batch of eggs are fertilized.
Habitat
Shortfin mako sharks live in tropical and temperate offshore waters. They are a pelagic species that occur from the surface down to depths of 150 meters (490 feet). This shark is seldom found in waters colder than 16 degrees Celsius.
Range
The shortfin mako is found worldwide. In the western Atlantic it can be found from Argentina and the Gulf of Mexico to Browns Bank off of Nova Scotia. In Canadian waters these sharks are not abundant as they prefer warm waters, but neither are they rare. Shortfin makos are often found in the same waters as swordfish as they are a source of food and both fish prefer similar environmental conditions.

School Shark

School Shark :
Size: Up to 6ft long
Weight: Unknown
Food Sources: Bony fish
Habitat: Deep waters 550 m (1,800 ft)
Locations: Western Atlantic: southern Brazil to Argentina
Interesting Facts: None